POSITIVE PHOTOSENSITIVE POLYIMIDES USING POLYAMIC ACID-ESTERS WITH PHENOL MOIETIES

Polyimide resists developable with basic aqueous solutions were realiz ed by polyamic acid esters with phenol moieties (PPh's) and naphthoqui none diazides. The polyimide precursors (PPh's) were synthesized from diamines and dicarboxylic acids that have phenol moieties through este r linkage. A selective reaction of alcohol groups with acid dianhydrid e groups made the synthesis of the PPh's possible, even if the phenol groups were in the reaction mixtures. The PPh's were soluble in basic aqueous developer, but their dissolution rates were too low for use as resists. To increase the resist dissolution rate, polyamic acids were added to the PPh's. By adjusting the dissolution rates in basic aqueo us developers, fine patterns could be realized. The polyimide resists had high thermal stability and reliable adhesive property to silicon s ubstrate. (C) 1994 John Wiley & Sons, Inc.